Technical Field
The present disclosure relates to a rotating electric machine that is used, for example, as an electric motor or a power generator mounted in a vehicle.
Related Art
A rotating electric machine that is used as an electric motor or a power generator in a vehicle includes a rotor and a stator. The stator has a stator core and a stator winding. The stator core is disposed so as to oppose the rotor in a radial direction. The stator winding is wound around the stator core. In the rotating electric machine such as this, when a current flows through the stator winding, the stator winding generates heat, thereby causing the temperature of the stator to rise. Therefore, when the temperature of the stator rises to a predetermined temperature or higher, for example, some of the components configuring the stator may be damaged by heat.
Therefore, as disclosed in JP-A-2008-131775, setting a temperature detecting element in the stator and detecting the temperature of the stator is publically known. In JP-A-2008-131775, the temperature detecting element is attached such that a sensor unit thereof is covered by a heat conducting portion of a metal member. Heat transmitted to the heat conducting portion is quickly conducted to the sensor unit from the periphery of the sensor unit, thereby increasing response speed. When the temperature of the stator rises and the temperature detected by the temperature detecting element reaches a predetermined temperature, in an electric motor, for example, the current supplied to the stator winding is cut off and temperature increase in the stator is prevented.
In addition, as a method for cooling the stator, using a cooling apparatus that cools the stator by dripping a liquid coolant onto the coil end portions of the stator winding that project outside from both end surfaces in an axial direction of the stator core is also publically known.
In a rotating electric machine that uses the cooling apparatus to cool the stator using a liquid coolant, when the liquid coolant that is dripped onto the coil end portions of the stator winding hits the temperature detecting element, the temperature detecting element detects the temperature of the liquid coolant rather than the temperature of the stator winding. Therefore, an error occurs between the actual temperature of the stator winding and the temperature detected by the temperature detecting element. However, to prevent heat-attributed damage to the constituent components of the stator, heat generation in the stator winding is required to be suppressed when a temperature that is lower than the usage temperature limit by an amount equivalent to the error is detected. Therefore, when the error increases, the capabilities of the rotating electric machine cannot be sufficiently realized.
To prevent the temperature detecting element from being hit with the liquid coolant, providing a coolant guiding member or the like can be considered. However, when the coolant guiding member is provided, component cost and assembly cost may increase due to this additional member, and the physical size may increase because additional installation space is required. In addition, the coolant guiding member is attached to the housing or the like of the rotating electric machine. Thus, the coolant guiding member contributes to damage caused by vibrations, and significant labor is required to confirm reliability. Furthermore, the coolant guiding member shortens a creepage distance between windings of differing phases. Thus, insulation performance may decrease.